1. Field of the Invention
The present invention relates to a copying apparatus, a facsimile apparatus, a printer, or the like, utilizing an electrostatic image transfer process, and more specifically to an image forming apparatus that includes at least first and second image forming devices each including a photosensitive member, a charging device to charge a surface of the photosensitive member, and a lubricant supplying device to supply a lubricant to the surface of the photosensitive member, respectively.
2. Discussion of the Background
Japan Laid-Open Patent Publication no. 2001-051467 discloses a color image forming apparatus having a plurality of image forming devices. A constitution of a charging device of one of the plurality of image forming sections is different from a constitution of a charging device of the other plurality of image forming sections.
The image forming device used for forming black images has a charging unit that includes a non-contact type charging wire to have applied a charging bias having a direct current component, and the other image forming devices used for forming color images have a contact type charging unit that includes a charging roller to have applied a charging bias having an alternate current component and a direct current component.
Japan Laid-Open Patent Publication no. 2000-338819 discloses a color image forming apparatus that includes a lubricant supplying device, which can decrease a wear of a photosensitive member, improve a cleaning efficiency of residual toner on the photosensitive member after transferring, and prevent filming and adhesion of toner components on the surface of the photosensitive member.
It is common that a plurality of the image forming devices include a lubricant supplying device having the same constitution.